The Cancer Immunotherapy Trials Network (CITN), a multi-institutional consortium, focuses on early-phase clinical trials that test immunotherapeutic agents and modalities to treat patients with cancer. The Central Operations and Statistical Center (COSC) of the CITN will be based at the Fred Hutchinson Cancer Research Center (FHCRC). The COSC will provide leadership and organizational resources, including infrastructure, statistical support, and protocol coordination, for up to 25 member institutions and tumor immunology laboratories throughout the US. The research goals include: (1) creating and managing the CITN COSC to run a network of leading investigators and institutions to conduct early-phase clinical trials to determine the safety, toxicity, and efficacy of promising agents and strategies to prevent and treat cancer by immune mechanisms; (2) initiating at least 15 phase I or early phase II trials over the course of the funding period that investigate the basic mechanisms of immune evasion and resistance of cancers as an integral part of clinical trials; and (3) integrating a number of tumor immunology laboratories into the CITN to enable the use of specimens obtained from patients on CITN clinical trials for immunomonitoring, biomarker development and credentialing, and facilitating an understanding of the biological mechanisms that underlie the results of the clinical trials. A major strategy will be to proactively choose the best peer-reviewed concepts from the broad immunotherapy community and use the collective experience of the CITN Steering Committee to construct ideal protocols including use of hard-to-get prioritized immunotherapy agents. The PI and Co-Investigators combine long successful histories of multicenter clinical trial conduct, early-phase immunotherapy research, and good laboratory practice and monitoring. The CITN will model the best practices and collaborate directly with scientists and management of the FHCRC-based HIV Vaccine Trials Network, an international consortium that conducts HIV-related immunotherapeutic clinical trials.